Eminent anole researcher Robin Andrews was recognized by the Herpetologists’ League with the 2021 Distinguished Herpetologist Award for her contributions to advancing scientific and public understanding of herpetology through research, teaching, and service. Her essay in Herpetologica chronicles the incredible, 50-year-long research program she, Stan Rand and others have conducted on Anolis apletothallus on Barro Colorado Island in Panama.
Here’s the Abstract:
I present the results of 50 yr (1971–2020) of annual censuses of Anolis apletophallus on Barro Colorado Island, Panama. The main objectives were to assess why abundance in end-of-the-year censuses varied substantially from year to year and why it declined over time. Abundance was negatively correlated with annual rainfall, 90% of which occurs in the wet season when eggs are laid. Lizard abundance is indirectly linked to rainfall through the interaction between Anolis eggs and their major predator, Solenopsis ants. More eggs are killed by ants when rainfall is relatively high because ants are more active and encounter more eggs than when rainfall is relatively low. While rainfall accounts for variability in abundance, it has not changed over time and thus may not account for the overall decline in abundance. Model selection of AICc analyses identified two other factors correlated with abundance. Abundance was positively correlated with the Southern Oscillation Index (SOI) lagged by 1 yr. High SOI (and high abundance) is associated with cool and wet La Niña conditions and low values with dry and warm El Niño conditions. The prediction that low abundance is associated with dry and warm El Niño conditions (low SOI) conflicts with the negative correlation between abundance and rainfall where low abundance is associated with high rainfall. Moreover, abundance was negatively correlated with Tmin (minimum annual temperature). The mechanism by which increasing Tmin during the census period is linked to declining abundance is unknown. Three climatic factors are correlated with lizard abundance, but none of them explain why abundance has declined. A third objective was to examine the relationship between species richness and species dominance of Anolis communities with respect to rainfall patterns. Tropical forests typically have a maximal richness of 7–8 species. Our study sites in Panama have high species richness, but Anolis apletophallus individuals made up 96% of all records, an unexpected level of species dominance. Comparisons among sites suggest that the number of Anolis species in a community is related to annual rainfall, and dominance is related to seasonality of rainfall. Dry forests have few Anolis species and wet forests have as many as 7–8 species. Forests with short wet seasons (months with .100 mm rainfall) have a high likelihood that individuals of one species will dominate the community.
As the abstract reveals, the paper summarizes an extraordinary amount of fascinating research. But there are also some great stories. This is my favorite:
My trip to Panama to conduct the Christmas lizard count with Stan was normally a very special and much anticipated annual treat. One such year, however, was far different from the treat I had anticipated. I had taken my Boston Whaler, on what was to have been a quick trip to our remote AVA site to replace fallen flagging tape that marked transects. This was a boat trip of some 9 km from the BCI boat dock on the canal (northeastern) side of the island to the AVA boat tie up on the back (southwestern) side of the island. My mission accomplished, I left AVA midafternoon and was close to the half-way point when the motor of the Boston Whaler quit. Not only was I alone on the back side of BCI, but the strong dry season wind was pushing the boat away from BCI. To stop the boat from drifting farther, I used its single oar to steer it to the nearest channel marker where I tied up. I had faint hopes of rescue because boat traffic was infrequent; the most likely scenario was that I would sit in the boat until nightfall when the wind would die down and I could start to paddle. This is exactly what happened. Progress around BCI was very slow because I had to sit on the prow of the Whaler and pull the boat forward with the oar while alternating strokes from one side of the boat to the other to maintain a somewhat straight course. It was thus quite dark when I saw the first of many waves of large, low-flying aircraft pass overhead. I heard the steady drone of the air traffic and felt extremely isolated in my small boat in the dark. I did not know until the next day that, in the early hours of 20 December, I witnessed the beginning of the 1989 US invasion of Panama!
It was well after midnight when, to my great relief, I was intercepted by BCI guards on their regular island patrol just as I saw the buoy lights of the canal; the guards towed me the last several kilometers of what had been a physically and mentally challenging journey. The next day BCI was deemed unsafe and all scientists, guards, cooks (and their food supplies), etc. were ordered to leave the island by the Smithsonian. For the first time in its history as a nature reserve, the island’s biota was left to its own devices. All the island boats were commandeered to take the residents of BCI to Gamboa (Fig. 3), one of the initial targets for US military action. When we were allowed outside, we visited the remains of a Panama Defense Forces building and saw what automatic rifle fire could do to the simple wooden walls and floors of standard issue Panama Canal Company buildings. That memory became especially vivid on that evening when our group was taking shelter in the concrete stairwell of just such a building because of nearby sniper fire. Panama City and rural areas were so chaotic that the Panamanian evacuees could not go home to their families, not even to know, in some cases, if they were safe. Despite these challenges, the cooks continued to produce great meals for us, including a turkey dinner on Christmas Day. At the end ofDecember, we were allowed to return to BCI. The Anolis team completed the scheduled censusing of four sites, but what remained of my vacation time was too short to conduct planned experimental studies. I was on the first commercial flight to the United States after the invasion, and, for the very first time, I was happy to leave Panama.
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